Norway has announced plans to build the world's first tunnel for ships.

The 1,700m (5,610ft) passageway will burrow through a piece of rocky peninsula that will allow vessels to avoid a treacherous part of the sea.

The Stad Ship Tunnel would be able to accommodate cruise and freight ships weighing up to 16,000 tons.

It will be 36 metres (118 feet) wide and 49 metres (162 feet) tall and is estimated to cost at least 2.7 billion kroner (£252 million).

Norwegian transportation minister Ketil Solvik-Olsen said that sea currents and underwater topography in this part of the country's south-western coast "result in particularly complex wave conditions".

"We are pleased that the ship tunnel now becomes reality," Mr Solvik-Olsen said, adding that travel time between Norwegian cities and towns in the area would be reduced.

Over the years, plans for a ship tunnel in Stad had been floated but now a project with financing is ready, he said.

The tunnel is expected to be located at the narrowest point of the Stadlandet peninsula.

Project manager Terje Andreassen said engineers will have to blast out an estimated eight million tons of rock to build the tunnel. Construction is expected to start at the earliest in 2019.

Under the plan, passenger traffic will be given priority but leisure boats and other vessels can also use the tunnel. It will be free of charge for vessels measuring less than 70 metres (230 feet), and vessels longer than that would have to be led.

Vessels sailing through the tunnel are likely to get slot times from a traffic centre - like planes at an airport - to avoid congestion.